I'd agree shep, it's all about responsible ownership, trouble is sometimes you think you've responsibly let your dog off lead, I.e. no unfenced livestock, but ones escaped the enclosure, seen by your dog and that's it they're off.
My collie and gsx have both got their kennel club gold good citizen awards, I tried with George but he failed his bronze, almost impossible to fail this, but being in a village hall with 10 other dogs was just too stimulating for him, at home you'd swear he'd pass his silver award
I always think that when they're on a walk they're in pack mode, ie like wolves going hunting, they're just waiting for you, the alpha dog, to give them permission to go for it, I don't think that instinct is breed specific, it's hard wired into all dogs